ATC 313: The Overtraining-Oxidative Stress Connection, A 30% Rule For Running–What Is It and Who Should Follow It, And Why Now The Time To Focus On Those Weaknesses

June 19, 2020


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A fun challenge because why not: How close can you get to running 10k on the dot without looking at your GPS or watch? The rules are: NO well-known routes, it must include hills and of course you can not have a stopwatch or a map! Cover your watch. Press start and run until you think you’ve covered 10k.

Study discussion:

  • Intramuscular mechanisms of overtraining
  • Published Jan 2020
  • From the study: “the purpose of this review is to discuss potential underlying mechanisms that may contribute to exercise-induced overtraining syndrome (OTS) in skeletal muscle.”
    • Prevalence
      • Studies report that ~30% of both young athletes (< 18 years) and elite athletes (> 18 years old) have experienced overreaching/OTS at least once [6–9]. However a prevalence of as high as ~60% in male and female elite runners have been described [10].
    • Defining OTS
      • Persistent underperformance despite > 2 months of recovery,
      • Changes in mood
      • Absence of symptoms/diagnosis of other possible causes of underperformance [8,9,11,12].
    • OTS has been attributed to both central (psychological, neurological) and peripheral (intramuscular) mechanisms [8,9,11,12].
      • The major proposed mechanisms underlying skeletal muscle weakness in OTS:
        1. Glycogen depletion hypothesis- contributes but not enough to explain mechanism nor directly cause.
        2. Muscle damage hypothesis- Mechanical damage not directly responsible for exercise-induced loss of force or OTS; not a direct cause.
        3. Inflammation hypothesis- Thus, repeated strenuous exercise can induce a persistent intramuscular molecular cytokine signature, which shares commonalities with disease states of chronic inflammation (e.g. rheumatoid arthritis [80]) which is accompanied by muscle weakness [76–78,80]. As a result, repeated strenuous physical activity with too short recovery periods that induces soluble factors which prolongs the duration of inflammation will most certainly lead to decreased muscle function and may well be a key component in OTS.
        4. The oxidative stress hypothesis- Similar to chronic disease, OTS may represent a state of chronic oxidative stress. For instance, blood markers of oxidative stress (e.g. depletion of reduced glutathione (GSH)) can persist for longer than a month following an ultra-endurance running event [100].
    • Conclusion: “Current data implicates reactive oxygen and nitrogen species (ROS) and inflammatory pathways as the most likely mechanisms contributing to OTS in skeletal muscle. Finally, we allude to potential interventions that can mitigate OTS in skeletal muscle.”
    • Inflammation
      • For instance, over-expression of IL-6 causing chronically elevated IL-6 levels in skeletal muscle, results in lowered force production, reduced expression of proteins in the mitochondrial electron transport chain, and diminished respiratory capacity [81].
      • Moreover, exercise-induced muscle damage can persist for weeks and trigger macrophage activation where several cytokines (incl. TNFα, IFNγ, IL-6, and IL-10), appear to be involved [44,50,63,64].
    • VICIOUS CYCLE: Cytokines are known to increase the production of reactive oxygen species (ROS) and in turn, ROS can promote release of pro-inflammatory cytokines [67,80,84–86]. (And process continues)
      • ROS can cause an imbalance in the redox state of the muscle, resulting in impaired exercise performance as evident in athletes with OTS [12,87].
    • One solution to mitigate OTS: use of antioxidants to alleviate the oxidative stress. “We acknowledge that antioxidants (e.g., vitamin C and E) given to healthy individuals can have detrimental effects on endurance training adaptations [94–96]. However, here we imply that OTS more closely resembles a state of chronically elevated oxidative stress, such as in chronic disease, rather than exercise adaptation.
      • Antioxidants and anti-inflammatory compounds may show promise in neutralizing the elevated oxidative stress and chronic inflammation in muscles of athletes with OTS, although further research is required.
    • Of note: Many articles referenced were rat studies, and OTS is a HUMAN condition that is about more than muscle physiology.

Jessie asks:

The 30% rule for running and should we follow it

This rule states that your weekend long run should be no more than 30% of your total weekly volume. How and why this is, where does it apply (eg triathlete vs runner), when should it be considered (eg running durability), etc.

What the Coaches say:

  • Even though this percentage is a good general rule, it might not always be appropriate based on specific circumstances.
  • This rule is in place to protect you. But if you can safely break it, then do it. Be honest about your durability.
  • Triathletes especially can break this rule, because their time on the bike takes away from run volume. This rule would probably be unrealistic for most triathletes, though it would work better for pure runners.
  • What’s the effect of pushing that volume? If you do excessive volume on your long run, then have to take several days off to recover, then you need to shorten the long run.

Kenaia N. asks:

How to train with the goal of improvement when there are no races?

Hi! I absolutely love your podcast and have a question I’m hoping you’ll be able to answer…

This is probably on a lot of people’s minds at the moment, but I’m curious what the smartest way to train right now is, when races are cancelled and it’s hard to know what to plan for.

My own dilemma is this: I was planning on racing Boston and New York this year as my spring and fall races. As things stand now, I’m planning on racing Boston in the fall and just giving New York my best after that. I’m training like these races are going to happen, building up to 80 mile weeks, incorporating speed work where it will be appropriate, etc. But my fear is that one or both will end up being cancelled.

I understand how to write a periodized training plan, but how do I train to improve if there are no races (specifically, when there are no marathons)? My end goal is to qualify for the Olympic Trials in the next 4 years (the qualifying time is 2:45 for women). If Boston and/or New York are cancelled, would it be smarter to just run steady base mileage until I can target a specific race? Should I create shorter-distance time trials for myself? Obviously this is a hypothetical as both races are still currently scheduled, but I’d love to know your thoughts on how to train for an end goal without the benchmarks races give us.

What the Coaches say:

  • You’re tying training and improvement to racing, but that’s not necessary. You can gauge improvement by looking at training blocks.
  • For athletes who are trained for long distance, their weakness is normally speed.
    • Stepping back and doing a speed focus will not detract from your endurance. It will actually make you a stronger athlete to work on 1-mile and 5-mile speed.
  • What is limiting you from running 2:45? It’s not volume, but speed.
  • There’s no “right” training right now. “Appropriate training” is based on the assumption that you have a race X days out. Since there are no races, there’s no wrong way to train (as long as you don’t get hurt). Right now you’re just training to train.
  • Note to everyone right now: Do NOT train for your goal race, since we don’t know when they’re going to happen!

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